WO2024032003A1

WO2024032003A1 - Large-section railway tunnel surrounding rock stability control method

Info

Publication number: WO2024032003A1
Application number: PCT/CN2023/084254
Authority: WO
Inventors: 祁子鹏; 袁义华; 郭建群; 武进广; 郭炜欣; 邹明; 向凯; 高凯恒; 陈强; 廖理阳; 李玉强; 李济辰; 陆鑫; 孙浩铭
Original assignee: 中铁七局集团有限公司; 中铁七局集团第四工程有限公司
Priority date: 2022-08-11
Filing date: 2023-03-28
Publication date: 2024-02-15
Also published as: CN115680705A; LU504639B1

Abstract

A large-section railway tunnel surrounding rock stability control method, comprising the following steps: step S1, using a soil strength device to measure the strength of soil in a tunnel; step S2, demarcating crushed areas of which soil strength is lower than a preset threshold and marking same as low-strength areas, and demarcating an area of which soil strength is higher than the preset threshold and marking same as a high-strength area; step S3, according to different strength parameters of the low-strength areas, calculating the amount of a grouting material needing to be grouted into the low-strength areas so as to reach the same strength, and grouting the corresponding amount of the grouting material into the low-strength areas; step S4, covering the surfaces of the low-strength areas with glass fiber cloths; and step S5, coating a concrete layer, and performing targeted grouting according to different strength of different crushed areas, so that the crushed areas having different strength are reinforced and then can reach consistent strength, and finally the purpose of uniformly strengthening the tunnel is achieved.

Description

A stability control method for surrounding rock in large-section railway tunnels

Technical field

The invention relates to the field of stability control of tunnel surrounding rock. More specifically, the present invention relates to a method for controlling the stability of surrounding rock in large-section railway tunnels.

Background technique

With the rapid development of my country's railways, they have spread to all cities across the country. As of the end of 2021, the national railway operating mileage is 150,000 kilometers, including 40,000 kilometers of high-speed railways. Tunnels are required to be excavated when railways pass through mountainous areas. In large-section tunnels After excavation, the rock mass at the top of the cavern often undergoes large settlements, and the broken rock mass may even collapse or collapse, especially the rock mass around the shallowly buried and highly weathered underground tunnel, which is in a state of dense joints and extremely broken. , resulting in low subway construction efficiency and weakened surrounding rock support effect. The current reinforcement method for tunnel surrounding rock usually involves injecting grouting materials directly into the surrounding rock. This method is simple and practical, but the crushing conditions in different areas are different. If the same method is used for grouting without discrimination, it will inevitably lead to different areas. The strength is different, and if things go on like this, it will inevitably cause further cracking problems.

Contents of the invention

In order to achieve these objects and other advantages according to the present invention, a method for controlling the stability of surrounding rock of a large-section railway tunnel is provided, which includes the following steps:

Step S1: Examine the geological conditions of the surrounding rock of the railway tunnel, determine the properties of the tunnel soil, and use soil strength equipment to detect the strength in the tunnel;

Step S2: Divide the broken areas with soil strength lower than the predetermined threshold and mark them as low-strength areas, and mark them in order from high to low according to the strength parameters of each low-strength area, and mark the broken areas with soil strength higher than the predetermined threshold. Areas are demarcated and marked as high-intensity areas;

Step S3: According to the different strength parameters of each low-strength area, calculate the amount of grouting material that needs to be poured into each low-strength area to achieve the same strength, and inject the corresponding amount of grouting material into each low-strength area;

Step S4: After the grouting material is hardened to the first preset strength, the surface of the low-strength area is covered with glass fiber cloth, and anchors are used to fix the glass fiber cloth, and for each low-strength area, the glass fiber cloth is covering the low-strength area. At the same time, it also partially covers the high-intensity area adjacent to the low-intensity area;

Step S5: After the grouting material is completely hardened, apply a layer of concrete on the surface of all low-strength areas and high-strength areas.

Preferably, in the process of injecting grouting materials into low-strength areas, it is necessary to use drilling equipment to drill multiple grouting holes in each low-strength area, and then inject grouting materials through the grouting holes.

Preferably, when the strength parameter of a certain low-strength area is lower than a preset value, before using drilling equipment to drill grouting holes in the low-strength area, a thin layer of concrete needs to be sprayed on the surface of the low-strength area first. After the thin layer of concrete hardens to a certain hardness, drilling equipment is used for drilling operations.

Preferably, in low-strength areas, the higher the strength parameter, the greater the number of grouting holes that need to be drilled.

Preferably, in step S3, when the amount of grouting material injected by thermal storage in a certain low-strength area is higher than the set threshold, an anchor rod is inserted into the low-strength area during the filling process.

Preferably, after step S3, after a corresponding amount of grouting material is injected into each low-strength area, when the grouting material hardens to the second preset threshold, soil strength equipment is used to detect the strength of each low-strength area. If If the strength of a certain low-strength area is lower than the average and exceeds the preset range, the grouting material will continue to be injected. When the grouting material hardens to the second preset threshold, soil strength equipment will be used to detect the strength of the low-strength area, and the cycle The above operations are performed until the intensity of each low-intensity area is within the average range.

Preferably, step S5, coating a layer of concrete on the surface of all low-strength areas and high-strength areas, specifically includes the following operations:

Coat the first layer of concrete on the surface of all low-strength areas and high-strength areas, and then lay multiple steel mesh sheets on the surface before the first concrete layer hardens, and the parts between two adjacent steel mesh sheets Stacked, a rigid spring is used to connect the two at the stack.

Preferably, the second preset threshold is smaller than the first preset threshold.

Preferably, in step S4, multiple glass fiber cloths are laid, and two adjacent glass fiber cloths are partially stacked, and a flexible spring is used to connect the two stacked parts.

Preferably, the thickness of the glass fiber cloth is 3-5mm.

The present invention at least includes the following beneficial effects: The present invention performs targeted grouting according to the different strengths of different crushing areas, so that the crushing areas with different strengths can achieve relatively consistent strength after reinforcement treatment, and ultimately achieve the purpose of uniformly strengthening the tunnel.

Other advantages, objects, and features of the present invention will be apparent in part from the description below, and in part will be understood by those skilled in the art through study and practice of the present invention.

Detailed ways

The present invention will be further described in detail below with reference to the examples, so that those skilled in the art can implement it according to the text of the description.

The following description is provided to disclose the invention to enable those skilled in the art to practice the invention. The preferred embodiments in the following description are only examples, and those skilled in the art can think of other obvious modifications. The basic principles of the invention defined in the following description may be applied to other embodiments, variations, improvements, equivalents and other technical solutions without departing from the spirit and scope of the invention.

It should be understood that the term "a" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in other embodiments, the number of the element may be The number may be multiple, and the term "one" shall not be understood as a limitation on the number.

In actual construction, the crushing conditions of different areas of the tunnel surrounding rock are often different. Conventional reinforcement methods are to directly inject grouting materials equally and perform simple and rough reinforcement. However, there is a big problem with this reinforcement method, which is the crushing of different areas. Different situations will inevitably lead to different strengths. If the same method is used for perfusion without discrimination, it will inevitably lead to different strengths in different areas. If things go on like this, it will inevitably cause further cracking problems. In order to solve this technical problem, a preferred method of the present invention The implementation plan provides a method for controlling the stability of surrounding rock of a large-section railway tunnel, including the following steps:

Step S4: After the grouting material is hardened to the first preset strength, the surface of the low-strength area is covered with glass fiber cloth, and anchors are used to fix the glass fiber cloth, and for each low-strength area, the glass fiber cloth is covering the low-strength area. At the same time, it also partially covers the high-strength area adjacent to the low-strength area; the thickness of the glass fiber cloth is 3-5mm.

In the above embodiment, the traditional method of strengthening the surrounding rock of the tunnel and directly grouting all the broken areas without distinguishing the broken areas is abandoned. Instead, targeted grouting is carried out according to the different strengths of different broken areas, so as to achieve different strengths of crushing. After the area has been reinforced, it can reach a relatively consistent strength. Specifically, for low-strength areas with relatively lower strength, more grouting materials will be poured into them to improve their strength. For low-strength areas with relatively higher strength, more grouting materials will be poured into them. The relatively small amount of grouting material ultimately achieves the goal of uniformly strengthening the tunnel.

Grouting material refers to a fluid material that is injected under pressure into gaps and holes in strata, rocks or structures to increase bearing capacity, prevent leakage and improve the overall performance of structures. It can solidify. There is no restriction on the type of grouting material here. Conventional building grouting materials available on the market will suffice.

Among them, if the strength of the low-intensity area does not meet the standard, subsequent reinforcement processing is required. If the strength of the high-intensity area reaches the standard, subsequent reinforcement processing is not required. This threshold can be set according to the actual situation and is not limited here.

Among them, after the grouting material is hardened to the first preset strength, the surface of the low-strength area is covered with glass fiber cloth, and anchors are used to fix the glass fiber. Wire cloth uses the toughness of glass fiber cloth to increase the toughness of the area. After the grouting material hardens, the glass fiber cloth can deform to a certain extent to offset the stress, thereby reducing or avoiding the deformation caused by stress. And for each low-strength area, While covering the low-strength area, the glass fiber cloth also partially covers the high-strength area adjacent to the low-strength area. The glass fiber cloth is used to connect the high-strength area and the low-strength area at the same time, so that the low-strength area can also use high-strength areas. area of high intensity.

In a preferred embodiment of the present invention, during the process of injecting grouting materials into low-strength areas, it is necessary to use drilling equipment to drill multiple grouting holes in each low-strength area, and then inject grouting materials through the grouting holes.

In the above embodiment, it should be noted that during the drilling process, the speed must be kept constant and slow, otherwise excessive speed will inevitably cause collapse.

Considering that some low-strength areas have a high degree of fragmentation, if holes are drilled directly, they will easily collapse everywhere. In order to avoid this problem, a preferred embodiment of the present invention provides the following solution. When the strength of a certain low-strength area When the parameters are lower than the preset value, before using drilling equipment to drill grouting holes in the low-strength area, a thin layer of concrete needs to be sprayed on the surface of the low-strength area. After the thin layer of concrete hardens to a certain hardness, the grouting hole can be drilled. Drilling equipment performs drilling operations. The certain hardness here means that the thin layer of concrete there can provide certain support, but it can be cut and can be drilled by the drilling rig with a small drilling force. This allows drilling without causing collapse.

In a preferred embodiment of the present invention, in a low-strength area, the higher the strength parameter, the lower the strength, and naturally the greater the number of grouting holes that need to be drilled.

In a preferred embodiment of the present invention, in step S3, when the amount of grouting material for thermal storage and pouring in a certain low-strength area is higher than the set threshold, during the pouring process, an anchor rod is inserted into the low-strength area. , also to enhance performance.

In a preferred embodiment of the present invention, after step S3, after injecting a corresponding amount of grouting material into each low-strength area, when the grouting material hardens to the second preset threshold, soil strength equipment is used to detect each low-strength area. The strength of the strength area. If the strength of a low-strength area is lower than the average and exceeds the preset range, continue to inject grouting material. When the grouting material hardens to the second preset threshold, use soil strength equipment to detect the low strength area. For the intensity of the intensity area, cycle the above operations until the intensity of each low-intensity area is within the average range. The second preset threshold is smaller than the first preset threshold.

In a preferred embodiment of the present invention, the step S5, coating a layer of concrete on the surface of all low-strength areas and high-strength areas, specifically includes the following operations:

Coat the first layer of concrete on the surface of all low-strength areas and high-strength areas. Then, before the first layer of concrete hardens, lay multiple steel mesh sheets on its surface, and the parts between two adjacent steel mesh sheets. Stacked, the two stacks are connected using rigid springs.

When the steel mesh is embedded in the concrete, during the thermal expansion and contraction of the concrete, the slight deformation force of the steel mesh can offset part of the stress. When the stress is large, the strong deformation force of the rigid spring will It can offset the stress caused by thermal expansion and contraction inside the concrete, and the partial stacking between two adjacent steel mesh sheets. The process of staggering the two can also offset the stress caused by the thermal expansion and contraction inside the concrete, avoiding the effects of deformation stress. Concrete cracks.

In a preferred embodiment of the present invention, in step S4, multiple glass fiber cloths are laid, and two adjacent glass fiber cloths are partially stacked, and a flexible spring is used to connect the two stacked parts.

Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the description and embodiments. They can be applied to various fields suitable for the present invention. For those familiar with the art, they can easily Additional modifications may be made, and the invention is therefore not limited to the specific details and embodiments shown and described herein without departing from the general concept defined by the claims and equivalent scope.

Claims

A stability control method for surrounding rock of a large-section railway tunnel, which is characterized by including the following steps:

Step S1: Examine the geological conditions of the surrounding rock of the railway tunnel, determine the properties of the tunnel soil, and use soil strength equipment to detect the strength in the tunnel;

Step S2: Divide the broken areas with soil strength lower than the predetermined threshold and mark them as low-strength areas, and mark them in order from high to low according to the strength parameters of each low-strength area, and mark the broken areas with soil strength higher than the predetermined threshold. Areas are demarcated and marked as high-intensity areas;

Step S3: According to the different strength parameters of each low-strength area, calculate the amount of grouting material that needs to be poured into each low-strength area to achieve the same strength, and inject the corresponding amount of grouting material into each low-strength area;

Step S4: After the grouting material is hardened to the first preset strength, the surface of the low-strength area is covered with glass fiber cloth, and anchors are used to fix the glass fiber cloth, and for each low-strength area, the glass fiber cloth is covering the low-strength area. At the same time, it also partially covers the high-intensity area adjacent to the low-intensity area;

Step S5: After the grouting material is completely hardened, apply a layer of concrete on the surface of all low-strength areas and high-strength areas.
The method for controlling the stability of surrounding rock of large-section railway tunnels according to claim 1, characterized in that, in the process of injecting grouting materials into low-strength areas, it is necessary to use drilling equipment to drill multiple grouting holes in each low-strength area. , and then pour grouting material through the grouting hole.
The method for controlling the stability of surrounding rock of a large-section railway tunnel according to claim 2, characterized in that when the strength parameter of a certain low-strength area is lower than a preset value, drilling equipment is used to drill in the low-strength area. Before setting up grouting holes, a thin layer of concrete needs to be sprayed on the surface of the low-strength area. After the thin layer of concrete hardens to a certain hardness, drilling equipment can then be used for drilling.
The method for controlling the stability of surrounding rock of a large-section railway tunnel according to claim 1, characterized in that in the low-strength area, the higher the strength parameter, the greater the number of grouting holes that need to be drilled.
The method for controlling the stability of surrounding rock of a large-section railway tunnel according to claim 1, characterized in that in step S3, when the amount of grouting material injected with heat storage in a certain low-strength area is higher than the set threshold, During the pouring process, anchors are inserted into this low-strength area.
The method for controlling the stability of surrounding rock of a large-section railway tunnel according to claim 1, characterized in that after step S3, after a corresponding amount of grouting material is injected into each low-strength area, the grouting material is hardened to the second predetermined level. When setting the threshold, use soil strength equipment to detect the strength of each low-strength area. If the strength of one of the low-strength areas is lower than the average and exceeds the preset range, continue to inject grouting material until the grouting material hardens to the second When the threshold is preset, soil strength equipment is used to detect the intensity of the low-intensity area, and the above operations are cycled until the intensity of each low-intensity area is within the average range.
The method for controlling the stability of surrounding rock of a large-section railway tunnel according to claim 2, characterized in that step S5, coating a layer of concrete on the surface of all low-strength areas and high-strength areas, specifically includes the following operations :

Coat the first layer of concrete on the surface of all low-strength areas and high-strength areas, and then lay multiple steel mesh sheets on the surface before the first concrete layer hardens, and the parts between two adjacent steel mesh sheets Stacked, a rigid spring is used to connect the two at the stack.
The method for controlling the stability of surrounding rock of a large-section railway tunnel according to claim 6, wherein the second preset threshold is smaller than the first preset threshold.
The large-section railway tunnel surrounding rock stability control method according to claim 2, characterized in that, in the step S4, multiple glass fiber cloths are laid, and two adjacent glass fiber cloths are partially stacked. Use soft A sex spring makes the connection.
The method for controlling the stability of surrounding rock of a large-section railway tunnel according to claim 9, characterized in that the thickness of the glass fiber cloth is 3-5 mm.